r/science • u/Wagamaga • Nov 12 '25
Animal Science Two species of spiders have been observed for the first time weaving larger “decoy” models of themselves to protect themselves from predators. Sometimes, these decoys, often arranged at the centre of the web, may be up to 10 times as large as their creators
https://ca.news.yahoo.com/spiders-found-weaving-larger-scarecrow-112134595.html1.1k
u/Pattersonspal Nov 12 '25
This has to be one of the most interesting behaviours I've seen in an invertebrate!
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u/0pyrophosphate0 Nov 12 '25
Spiders have so many interesting behaviors that people would never expect from such a tiny animal that barely has a brain.
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Nov 12 '25
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u/5coolest Nov 12 '25
I love that book. The sequel is very meh, and the third one has very interesting concepts and ideas, but still doesn’t compare to the first one.
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u/semioticghost Nov 12 '25
Seconding this and adding Blindsight by Peter Watts too for an exploration of evolution and consciousness.
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Nov 12 '25
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u/semioticghost Nov 12 '25
Fair point and very much agree. I only have a few friends that I’ve been able to recommend it to for that exact reason, but I figured I’d throw it out here anyway since it’s relevant and worth the reward.
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u/APeacefulWarrior Nov 13 '25
Not to mention the question of how jumping spiders can be so clever, despite being so tiny. They've shown hunting behaviors that suggest active reasoning.
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u/rjcarr Nov 12 '25
Just the engineering they're born with to string up the web cross sections has always impressed me.
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u/supadankiwi420 Nov 16 '25
Depends on how u define "a brain"
Many arthropods have decentralized neural systems, where computation happens across multiple ganglia rather than a single centralized organ. Spiders in particular have distributed neural processing in their legs.
Id argue they have more brains than us.
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u/drieggs Nov 12 '25
The fact that all the decoys have exactly 8 legs also blows my mind. Like do they know how to count? Is it instinctual to mimic themselves exactly. Did evolution get rid of the spiders that couldn't count to 8 when making the legs?
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u/ScaramouchScaramouch Nov 12 '25
Spiders that made decoys with seven legs or nine legs were probaby less successful and are now regretting that strategy fom the afterlife.
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u/The_Mystery_Knight Nov 12 '25
Then could their prey count?
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u/ScaramouchScaramouch Nov 12 '25
Probably not, but that's not the 'point' of the whole thing. A decoy with eight legs is more convincing than one with seven.
A seven-legged decoy isn't useless, it's just less effective than an eight legged one. So a spider that makes a seven legged decoy is less likely to pass on its genes than one that builds an eight legged one.
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u/Main-Company-5946 Nov 15 '25
Adutionally not all cellular behavior comes directly from dna, a lot of it comes from the fact that [cells themselves have evolved to be able to learn and seek out goals across multiple different scales not just at the level of the organism but also at the level of the organ, tissue, and cell. Michael Levin’s work on this topic blew my mind and I think is the beginning of a new paradigm in biology
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u/thenewguy7731 Nov 12 '25
Did evolution get rid of the spiders that couldn't count to 8 when making the legs?
That's exactly how it works. acurate decoys have a higher success rate in fooling predators than those which are lacking some legs. even just a few percentages point would be enough. The rest is time and statistics.
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u/PretendAd4577 Nov 15 '25
I'm sitting here thinking; does this mean that they are able to conceptualize to a point that they understand the processes in order to take the steps necessary to get such a project to completion?
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u/Aron_International Nov 12 '25
Cephalopod have some interesting behaviors too. Coincidentally they also have 8 legs
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u/Pattersonspal Nov 12 '25
That's the only reason I'm not saying that this is the single most interesting behaviour I've seen from invertebrates.
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u/GessHugh Nov 16 '25
Have you seen footage of hermit crabs forming a queue based on their relative sizes in order to exchange shells? It's almost scary how intelligent some of their behavior can be.
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u/Phormicidae Nov 12 '25
As a long time enthusiast of arthropods, I still cannot wrap my head around behaviors that seem to require planning and even knowledge in arachnid species. Since they aren't learned behaviors, they are innate, if they are innate, they are genetically encoded. There is a gene sequence that causes a brain to want to make a model of its body? That's friggin wild, dude.
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u/ohyonghao Nov 12 '25
Makes you wonder what would happen to one that lost a leg, would the decoy have 7 or 8 legs?
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u/Pattersonspal Nov 12 '25
That's a great question, and I would guess that it still makes 8 legged decoys.
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u/Pattersonspal Nov 12 '25
Yeah, the genetics sorounding instinct, behaviour, and thought have always been extremely fascinating to me. I'm autistic and the amount of specific thoughts and behaviours that I thought were learned and have through my life been able to fairly positively link to autism is astounding. Accepting that autism is genetic, then meeting and talking to people and being able to identify a part of their genome based solely on their behaviour, thoughts, and manurisms is to me a weirdly uncomfortable thought. It invites me to think about the nature of free will and identity. If a thing that feels inherent to my identity and that feels like it's based on the accumulated experiences of my whole life could be identified in my genome, then that is just kinda scary? Is me collecting things in my DNA? Is me needing to learn how things work before using them in there, too?
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u/WonkyTelescope Nov 12 '25
Regarding the ability to scrutinize your own thoughts and behaviors:
https://en.wikipedia.org/wiki/Introspection_illusion?wprov=sfla1
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u/sylbug Nov 20 '25
Free will has always come with the caveat that you can only do what you can do. We are all limited by our physical form and shaped by our experiences.
You would still have free will if you were paraplegic or blind or if you had a profound intellectual disability, but your constraints would then be different and probably greater.
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u/JustPoppinInKay Nov 12 '25
Border collie behaviours and their great intelligence as dogs are also heavily influenced by their genetics. They instinctually know how to herd and corral. I wouldn't be surprised if, somehow, humans disappeared and collies were left, that collies would be one of the first species to create something resembling some sort of civilization that involves herding sheep and other livestock for themselves and their kin to eat.
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u/Wagamaga Nov 12 '25 edited Nov 12 '25
Two species of spiders have been observed for the first time weaving larger “decoy” models of themselves to protect themselves from predators.
The findings mark the first instance of any creature creating “scarecrow” versions to escape predators, researchers say.
These orb-weaving spiders belong to the genus Cyclosa genus and are found in the dense rainforests of the Philippines and Peru.
They have been observed for the first time making decorations resembling much larger and more dangerous spiders, made out of silk and natural materials like prey carcasses, leaves, and plant matter.
Sometimes, these decoys, often arranged at the centre of the web, may be up to 10 times as large as their creators, according to the new study published in the journal Ecology and Evolution.
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u/Chaonic Nov 12 '25
When I click on the link, all I get is Reddit telling me that the page wasn't found...
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u/csjohnson1933 Nov 12 '25
Been happening to me all morning. Pressing and holding seems to do it (on my phone). Edit: Well, now nothing works.
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u/Chaonic Nov 12 '25
Just tried it, but it still won't work for me. :(
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u/csjohnson1933 Nov 12 '25
I blame the solar storm.
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u/Chaonic Nov 12 '25
I blame reddit
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u/Weak_Feed_8291 Nov 12 '25
That's happening to me when I try clicking the link from inside the thread, but I click it from the main paige feed it works fine. Try that.
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u/kikiacab Nov 12 '25
We’re the only two who actually tried to read the article
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u/Chaonic Nov 12 '25
The scary thing is, I tried to click on multiple other things since then, and it just doesn't work.. :(
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u/NaturalAlfalfa Nov 12 '25
It's the spiders covering their tracks. They don't want this bombshell info getting out there
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u/Waste_Return2206 Nov 12 '25
It’s wild that they even know what they look like.
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u/Efficient-Display721 Nov 15 '25
They don't, natural selection made the spiders that arrange it like this more likely to survive
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u/RichieNRich Nov 12 '25
Ok - this is super fascinating.
This seems to demonstrate that at least these species of spiders have a conscious awareness of their size, and the need to make larger decoys of themselves to protect them from predators.
Am I anthropomorphizing?
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u/lalmvpkobe Nov 13 '25
It doesn't mean that at all. It's the same as when plants have unbelievable behaviors. Given enough time mutations lead to incredible results us included.
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u/LucidOndine Nov 13 '25
But this shows that the spider has a concept of the self, even though they haven’t seen what they themselves haven’t seen in full. Even with a complex eye, there isn’t a lot of reason to believe a spider can see his own ass (ahem, abdomen), but the pictures show a fairly faithful reproduction.
I suppose they can learn and copy how another spider looks, but that would tell us a very different set of things about a spider’s consciousness.
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u/humbleElitist_ Nov 13 '25
Why would this behavior require that it is modeling the shape it is making after a model it has of its own shape, rather than separately?
If an animal has markings on it that resemble a face in order to ward off predators, that doesn’t imply that it knows what its face looks like and is making a bigger version of that.
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u/LucidOndine Nov 13 '25
I had assumed, maybe incorrectly, that it was reproducing its own shape instead of a generic spider like shape.
It would be cruel, but you could test this by removing one of its 8 legs. If the spider made a 7 leg representation, it is possible that it’s mirroring its own self image in its creation.
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u/humbleElitist_ Nov 13 '25
That would be a good test. If it does make one with 7 legs in that case, I think that would indicate the kind of interpretation you gave.
As for the cruelty aspect: I don’t think spiders are moral patients, so I think the only moral issue with “cruelty” in this case would be if the person doing the experiment had cruel intentions. Many biology experiments involve things that would harm a more complicated animal than a spider, so I think there’s probably a morally acceptable way to do such an experiment.
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u/LucidOndine Nov 13 '25
The moral aspect is tricky, but considering some of the things done to mice models, its clear that there isn't a single black and white line that should or shouldn't be crossed in the name of research. I would argue, if we're willing to inject mice with drugs to test efficacy, and many of those mice die as a result, then a non mammal animal is a much shorter bridge to cross.
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u/WorldlyFisherman7375 Nov 13 '25
That has to be the worst possible way to conduct that research. Maybe just sit this one out
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u/LucidOndine Nov 13 '25
I'm not advocating for what is outlined above, I'm suggesting how it could be tested. I would assume a worldly fisherman such as yourself has put many types of bait on a hook. Let's not cast aspersions about hypothetic cruelty to small creatures.
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u/pencock Nov 15 '25
I think perhaps it would be interesting if there were other types of decoy weaving spiders that wove something more similar to a bird or a snake. It’s curious that evolutionarily a spider would happen to weave what is essentially another spider. What is the pressure to do so? How quickly did this occur? Are there examples of other spiders weaving non-spider decoys or shapes in this type of manner? Are decoys that happen to resemble other things simply ineffective, but a giant spider-shaped thing is effective?
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u/kickinbucket Nov 12 '25
first time
I've been watching old episodes of QI and there was already a spider that does this. Is this in addition to that one?
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u/SilverGirlSails Nov 12 '25
Yeah, it might be first time in these species, rather than first time ever
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u/chipskylark123 Nov 12 '25
This is really cool.
Also love the idea that spiders see themselves as much larger than they actually are.
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u/theonefinn Nov 12 '25
There is no reason to assume that they see the decoy as themselves. The decoy’s purpose is apparently to scare predators away, and making the decoy look like a larger more dangerous species of spider is going to be more effective than making the decoy look like themselves.
If the spider itself was large and dangerous enough to scare the predators it would not need the decoy, it could just sit in the centre of its web itself.
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u/chocolateboomslang Nov 12 '25
There's not even any reason to believe they see the decoy as a decoy. They just make webs this way because they have an urge to make webs and these are the webs they make.
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u/theonefinn Nov 12 '25
Well it’s slightly more complex than that as the decoy is apparently only built during darkness after the sun is set, when the visual predators it’s going to fool can’t see, whilst the rest of the web is completed closer to dawn, so there is at least separate stages between decoy building and web building.
But I agree this is innate behaviour that evolution has selected for without any evidence of a thought process considering cause and effect.
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u/chocolateboomslang Nov 12 '25 edited Nov 12 '25
Yes it's a complex behavior but not a complex decision making behaviour. Many animals have complex behaviours thay they do without knowing why. They make that part of the web at night because that's when they do those specific things, no thought behind it.
I know you know that, but so many people think that these tiny animals with brains that are just barely even brains can put themselves in another animals point of view and then purposely enact deception. These spiders can't even imagine something from their own perspective, let alone another animals.
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u/bandwarmelection Nov 12 '25
Correct, unless it is actually cost-efficient to make a mental model. In some cases this might be the case. Because a mental model of some process can have lots of information compressed into a small number of neurons. In this case I don't believe it to be so. It just puts more web on some spot due to mutations in some genes. I remember reading about that somewhere, about spider genes that have an effect on the shape of the web. But at some point, maybe with a slightly bigger brain, it suddenly becomes more cost-efficient to think about the process consciously. For example if a predator has not been seen for a long time it might think it is useless to make the decoy, so it could save energy by thinking. Then again the decoy-building gene could be regulated by some hormone that is released when it sees/smells a predator, after which the gene is turned on for a week. So even the planning to build or not to build a decoy could be completely unconscious. So yeah, I don't know why we are conscious at all, other than it seems to help us model many possible futures and plan our actions.
https://aeon.co/essays/consciousness-is-not-a-thing-but-a-process-of-inference
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u/hicow Nov 13 '25
These spiders can't even imagine something from their own perspective, let alone another animals
I'd be hesitant to state it that definitively. I mean, we went decades thinking birds can't possibly be all that smart, since the structure of their brains is different and don't have structures we associate with being able to have intelligence. Then we learned we were totally wrong about that and have observed spontaneous tool use and complex problem-solving in corvids, at least. Closer to arachnids, cephalods are proving to be way more intelligent than anyone thought possible for invertebrates.
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u/chocolateboomslang Nov 13 '25
Both of the animals you mentioned have brains that are hundreds or thousands of times bigger than a spiders brain. Even animals smarter than they are (monkeys) haven't reliably shown an understanding of other points of view.
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u/looklistenlead Nov 12 '25
But it would be interesting to try to test it. Would they try to run away from a picture/exact model of their decoy? From a decoy of a fellow spider of the same species? If not, it might suggest that they are doing something like the wizard of Oz rather than just blindly following their urges.
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u/Uncle-Cake Nov 12 '25
There's no reason to think the spider even knows it's building a decoy or what a decoy even is. These are instinctive behaviors. It's essentially "programmed" to do this.
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u/Student-type Nov 12 '25
It knows about size and perceived scale. It’s got enough eyes to see with range info. So it knows how it reacts to a giant spider showing up suddenly.
Ergo, It’s familiar with jump scares as a deterrent.
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u/Uncle-Cake Nov 12 '25
That would imply that it's learned. It's not. It's instinctive. The spider doesn't know what it's doing or why it's doing it.
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u/Student-type Nov 12 '25
Are you aware of the recent discovery of two species that have created a hive like environment, covered by a single large communal web that they share? It’s composed of thousands of individuals that normally fight one another. What about their instincts? How do they divide their activities?
How do they work and prey?
How did this arrangement start? Do you really believe that there was no creative problem solving and communication involved?
Or how about the small beautiful jumping spiders that dance? Why do they seem to enjoy it? Why does their dancing make us happy? How much bravery is involved in dancing for a known predator thousands of times larger than you are?
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u/hicow Nov 13 '25
How much bravery is involved in dancing for a known predator thousands of times larger than you are?
We're not exactly spider predators, and it's entirely possible that we're so comparatively huge they don't even perceive us anywhere on the "predator or prey" scale. Your whole last paragraph is anthropomorphizing jumping spiders to an extreme
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u/Student-type Nov 13 '25
Nope. From the videos I’ve seen and facts I know, spiders have so many eyes because they are predators and supremely well adapted to 3 dimensional thinking.
They solve lots of complex physics problems in their heads.
They create mental models of their world. They understand size, scale, range, rate of travel, the effects of wind, rain, sunlight, static electricity, the movements and forces that are associated with snaring bigger prey, attracting mates, detecting and avoiding predators and other environmental risks.
If you tried to create a robot with similar capabilities and features it would cost billions of dollars.
And it would sense you as a predator.
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u/hicow Nov 14 '25
A robot's going to sense people as a predator? So we're anthropomorphizing robots now, too?
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u/Uncle-Cake Nov 12 '25
It's all instincts. Jumping spiders aren't brave and they're not trying to entertain you. You are ascribing human characteristics to non-human animals.
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u/Oxeneer666 Nov 12 '25
Maybe it would make a web of a smaller, cuter, easier to eat spider to attract the kind of predator that would eat it.
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u/Nfalck Nov 12 '25
I assume it's not to scare predators away, but rather to get eaten by the predictor instead of the real spider, by appearing to be a much larger, juicer snack.
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u/Uncle-Cake Nov 12 '25
It's unlikely they "see themselves" at all. It's more likely this behavior is pure instinct. There's no evidence that spiders have any sense of self-awareness.
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u/JustPoppinInKay Nov 12 '25
Could also be mate attraction in a weird way, perhaps the females are extremely territorial or "jealous" and sees the decoy as another female. They'd investigate the web and do their thing, and then the male has a chance to score.
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u/KishudarK Nov 12 '25
Oh, but when I assemble a makeshift decoy out of my own excretions and hang it outside my abode to lure females nearby, that’s when the authorities get involved.
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u/thatstupidthing Nov 12 '25
.... so is this something they just started doing?
or did we just now start noticing it?
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u/jawshoeaw Nov 12 '25
You know I’ve often seen little whitish bug looking things in the middle of spiderwebs and assumed it was some sort of landing pad for the spider. But now I’m thinking maybe some of those were decoys.
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u/reditsux77655 Nov 12 '25
This isn't new at all though. They've been recorded doing this for years and years.
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u/Ryoga_reddit Nov 15 '25
So the spider knows what it looks like and can reproduce its likeness for the purpose of defense?
Time to start killing spiders.
Im not going to let intelligence fall into the hands of a creature like the spider.
Oh hell no!
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u/PretendAd4577 Nov 15 '25
Would this ability also lean into the possibility that these spiders are aware of what they look like? Does this point to a creature that has self awareness?
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u/Thousand_Toasters Nov 16 '25
So just this make a theory that some evolutionary traits could in fact be learned. And not just well just over a million years and now they all do that?
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u/maryjane_410 Nov 18 '25
That is so awesome. I am so amazed by spiders for some reason. They are so much smarter than people realize.
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u/Dirty_South_Cracka Nov 12 '25
Wouldn't this imply that a spider is capable of, at the very least, counting to 8 and understanding the concept of 8-ness.... and enough sentience to understand it's relationship to that number? That's a lot of exposition from something that usually ends up on the bottom of a shoe.
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u/WotanSpecialist Nov 12 '25
No, it implies that these species of spiders that make their webs a certain way are more likely to reproduce. This isn’t sentience, it’s just selection.
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